DSpace Collezione:http://hdl.handle.net/1889/658
Tue, 03 Mar 2015 22:36:38 GMT2015-03-03T22:36:38ZSomministrazione di farmaci a bambini e anziani: nuova tecnologia per prodotti estemporanei efffervescentihttp://hdl.handle.net/1889/2513
Titolo: Somministrazione di farmaci a bambini e anziani: nuova tecnologia per prodotti estemporanei efffervescenti
Autori: Torre, Eleonora
Abstract: È stata studiata una forma di dosaggio estemporanea effervescente. È stato ricercato un preparato solido, flessibile e versatile, che possa mantenere l’accuratezza di dosaggio e rendere possibile modulare la dose per adattarla al soggetto con problemi di deglutizione.
Un ulteriore obiettivo di questo progetto è stato l’innovazione del processo di fabbricazione dei prodotti effervescenti che richiede, al momento, per la manipolazione delle polveri e per il confezionamento del prodotto, tecnologie di condizionamento dell’aria e regole di svolgimento delle operazioni farmaceutiche molto rigorose.
Si è scelto quindi di utilizzare la tecnologia di fabbricazione farmaceutica di preparati solidi in forma di compresse, denominata Dome Matrix®. Essa si caratterizza per la fabbricazione di un preparato per il rilascio di farmaco ottenuto mediante l'assemblaggio di moduli di rilascio i quali contengono individualmente un solo principio attivo.
Inoltre, la struttura modulare può facilitare il processo di fabbricazione dei prodotti effervescenti. Infatti, si potranno sistemare le sostanze incompatibili in moduli diversi e combinare i diversi moduli o diverse composizioni in un solo prodotto in una fase di fabbricazione successiva.
Il prodotto finito disgrega velocemente a formare una soluzione/sospensione in un volume ridotto di acqua, perciò la formulazione dei singoli moduli è stata attentamente studiata, in quanto le sostanze per l'effervescenza non sono intimamente mescolate, ma collocate in moduli diversi seppur contigui uno all'altro.
Un altro aspetto importante, soprattutto perché i destinatari di questo prodotto sono i bambini è stato quello di conferire alla sospensione un sapore gradevole.
In questa tesi abbiamo scelto di formulare secondo i principi sopra esposti, farmaci destinati al trattamento della tubercolosi. In particolare sono stati preparati moduli contenenti, separatamente, isoniazide e rifampicina.
In definitiva, il prodotto effervescente che è stato realizzato vede la combinazione di 4 moduli, due di reagente acido con i dolcificanti e due contenenti separatamente i due farmaci. Quindi il combinato base serve per la somministrazione di 60 mg di rifampicina e 60 mg di isoniazide.; It has been studied an extemporaneous effervescent dosage form. It has been researched a solid, flexible and versatile form, that could maintain the accuracy of dose and could make possible to modulate the dose to fit the patient with swallowing problems .
A further objective of this project was the innovation of the process of manufacture effervescent products. The process of manufacture effervescent products requires, for the handling of powders and for the packaging of the products , to operate in air -conditioning areas. It is chosen to use the Dome Matrix ® technology to manufacture special tablets called modules. Each module of release individually contains only one active agent. The final product is an assemblage of several modules.
Moreover, the modular structure can facilitate the process of manufacture of effervescent products. It is possible to fix the incompatible substances in different modules and combine the different modules or different compositions in a single product in a subsequent stage of manufacture.
The final product disintegrates rapidly to form a solution / suspension in a small volume of water. The formulation of the individual modules has been carefully studied, because the substances for the effervescence are not intimately mixed, but placed in different modules.
Another important aspect, especially because the final users of this product are children was to give to the suspension a pleasant taste.
In this thesis we have chosen to formulate with the principles set out above, drugs for the treatment of tuberculosis. In particular modules were prepared containing, separately, isoniazid and rifampicin.
The effervescent product that has been achieved is a combination of 4 modules , two of acid reagent with sweeteners, and two containing the two drugs separately. So the combined product is suitable for the administration of 60 mg of rifampicin and 60 mg of isoniazid.Tue, 08 Apr 2014 22:00:00 GMThttp://hdl.handle.net/1889/25132014-04-08T22:00:00ZSistemi terapeutici innovativi per il trattamento delle lesioni cutaneehttp://hdl.handle.net/1889/2512
Titolo: Sistemi terapeutici innovativi per il trattamento delle lesioni cutanee
Autori: Mori, Michela
Abstract: A tutt’oggi non esistono trattamenti terapeutici soddisfacenti per la cura delle lesioni cutanee quali le ulcere cutanee croniche. Ulcere da decubito, neuropatiche e vascolari hanno un impatto importante sulla spesa sanitaria perchè la popolazione sta invecchiando e risultano frequenti le patologie croniche. In questo scenario il trattamento delle ulcere cutanee si sta progressivamente muovendo da un semplice trattamento sintomatico palliativo, basato sull’utilizzo di dispositivi medici e/o medicazioni tradizionali, ad un approccio più moderno definito con il termine di medicina riparativa. In questo ambito i fattori di crescita, ed in particolare i fattori di crescita piastrinici, hanno dimostrato di svolgere un ruolo importante nel processo di riparazione tissutale e l’impiego di emoderivati, come il plasma ricco in piastrine (PRP) ed il lisato piastrinico (LP), contenenti un pool di fattori di crescita, è sempre più spesso proposto nella pratica clinica per trattamenti di riparazione tissutale. È’ inoltre noto che l’efficacia di tali fattori di crescita dipende da come questi sono resi disponibili al sito d‘azione; risulta perciò di notevole importanza lo sviluppo di idonei veicoli.
Date queste premesse, lo scopo del lavoro di tesi è stato lo sviluppo di sistemi terapeutici innovativi basati sull’associazione di LP con biopolimeri per il trattamento delle lesioni cutanee.
La presente tesi è composta da un’introduzione e sei capitoli sperimentali. Nella parte introduttiva viene descritto lo stato dell’arte ed il razionale del lavoro di ricerca. Il I Capitolo tratta la messa a punto del metodo di proliferazione cellulare utilizzato per valutare l’attività biologica delle formulazioni caricate con LP e la stabilità di LP come tale e dopo liofilizzazione.
Nel II Capitolo è stata studiata la possibile associazione di LP con un farmaco antimicrobico modello, quale la vancomicina cloridrato (VCM). Per evitare problemi di incompatibilità fra l’emoderivato e l’antibiotico, è stata sviluppata una polvere aspersoria costituita da una miscela di particelle di alginato di calcio incapsulanti VCM o LP, ottenute separatamente per estrusione, gelificazione ionica e successiva liofilizzazione.
Nel III Capitolo, per ampliare le applicazioni terapeutiche dell’associazione tra LP e VCM, è stata sviluppata un medicazione assorbente costituita da capsule di ialuronato di sodio caricate con LP e inglobate in una medicazione di sodio alginato contenente VCM.
Nel IV e V Capitolo è stata valutata l’associazione tra chitosano e sericina, proteina della seta. Il razionale si basa sulla combinazione delle diverse e ben conosciute proprietà del chitosano con le proprietà antiossidanti e di proliferazione cellulare vantate dalla sericina. In particolare, nel Capitolo IV la composizione di una medicazione sponge-like a tre componenti (chitosano, sericina e glicina (utilizzata come criprotettore)) è stata ottimizzata utilizzando un disegno sperimentale (DoE) basato sul simplex centroid design. Le variabili ottimizzate sono state le proprietà di idratazione, reologiche e meccaniche. Nel Capitolo V la medicazione ottimizzata è stata caricata con LP mediante due differenti tecniche di caricamento. Nel primo caso, il LP è stato direttamente aggiunto ai componenti della formulazione prima della liofilizzazione; nel secondo caso il LP è stato caricato estemporaneamente sulla medicazione liofilizzata. È’ stata valutata l’influenza del caricamento di LP sulle proprietà di idratazione, reologiche e meccaniche della medicazione.
Nel VI Capitolo è stata studiata l’associazione tra sucralfato, LP e biopolimeri con lo scopo di valutare l’eventuale verificarsi di un effetto sinergico sul processo di riparazione. Il sucralfato, complesso metallorganico, è noto in letteratura per le proprietà riparative nei confronti di vari tessuti e proposto come polvere nel trattamento delle ulcere cutanee. All’inizio di questo studio, non esistevano dati di compatibilità fra LP e sostanze di natura inorganica o metallorganica.; There are still unmet needs in the treatment of epithelial and skin lesions, in particular chronic wounds of various etiology do not yet afford a satisfactory treatment. Decubitus sores, vascular and neuropathic ulcers represent a major health care burden, likely to increase as the population ages and becomes affected by chronic diseases. In this scenario, the treatment of epithelial and cutaneous lesions is progressively evolving from a symptomatic palliative approach, based on the use of medical devices and/or traditional drug products, towards a more modern approach, so-called reparative medicine. Within this frame growth factors and in particular platelet growth factors (GF) are known to play an important and delicate role in wound healing and the therapeutic employment of hemoderivatives such as platelet rich plasma preparations (PRP) and platelet lysate (PL), that contain a pool of growth factors, is being increasingly proposed in the clinical practice for various reparative treatments. It is also recognized that the efficacy of GFs critically depend on the way they are made available to the injured tissue. Therefore the development of suitable therapeutic vehicles is of paramount importance for allowing growth factors to be released according to the repairing requirements. Furthermore a successful treatment of chronic wounds often calls for the combined use of growth factors with antinfectives and/or antioxidants, which may need different release profiles, thus requiring an optimal design of the vehicle.
Given these premises, the aim of the work was the development of new therapeutic platforms based on the biopolymers intended to be associated with PL for the treatment of chronic wounds.
The thesis work consists in an introduction and six experimental chapters. In the introduction the background and the rationale for the research are outlined. Chapter I deals with the development of the cell proliferation method used for evaluating the biological activity of PL loaded formulations, including the evaluation of PL stability as such and after freeze drying.
In Chapter II the possible association of PL with an antimicrobial drug, vancomicin hydrochloride (VCM) was investigated. In order to avoid any incompatibilities between the two actives, a multiparticulate formulation composed of calcium alginate beads which were obtained by ionic gelation and separately loaded with VCM and PL was developed.
In Chapter III, in order to extend therapeutic applications, the above combination between PL and VCM was proposed as an absorbent dressing. This was made of hyaluronate capsules loaded with PL and embedded into a sodium alginate dressing containing VCM.
In Chapters IV e V the ssociation of chitosan and sericin, a protein derived from silk, was investigated. The rationale was to combine the wellknown multifunctionality of chitosan with the favourable proliferative and antioxidant properties of sericin.
In particular, in Chapter IV the composition of a three-component sponge like dressing made of chitosan, sericin and glycin (as crioprotectant agent) was optimized using a DoE approach based on a simplex centroid design. The optimized variables were hydration, viscoelasticity and mechanical properties. In Chapter V PL was loaded into the optimized dressing using two different loading technique. In the first case PL was directly added to the dressing components before freeze-drying; in the second case PL was added extemporaneously to the freeze-dried dressing. The influence of PL loading on hydration, rheological and mechanical properties was investigated.
In Chapter VI the possible association between sucralfate PL and biopolymers was investigated with the aim of exploiting the synergic effects of such combination on healing process. Sucralfate is a metallorganic complex molecule known for its protective properties on different tissues and has been proposed as a powder in the treatment of cutaneous ulcers. It is noted that, at the start of the present work, no data on the compatibility between inorganic materials and PL were available.Tue, 08 Apr 2014 22:00:00 GMThttp://hdl.handle.net/1889/25122014-04-08T22:00:00ZDesign and synthesis of human serine racemase inhibitors, a challenge to modulate NMDAR dysregulation and neurodegeneration induced.http://hdl.handle.net/1889/2511
Titolo: Design and synthesis of human serine racemase inhibitors, a challenge to modulate NMDAR dysregulation and neurodegeneration induced.
Autori: Pecchini, Chiara
Abstract: Mammalian Serine Racemase (SR) is a pyridoxal-5′-phosphate (PLP) dependent enzyme, responsible for the biosynthesis of the neurotransmitter D-Serine, which activates N-methyl-d-aspartate receptors (NMDAR) in the CNS.
Inhibition of SR could be a means to control D-Serine levels, which on turn may limit the NMDAR- mediated neurotoxicity in neurodegenerative diseases such as Alzheimer’s disease, amyotrophic lateral sclerosis, Parkinson’s disease, and protect against cerebral ischemia.
The aim of this work is to identify new compounds that can interact with SR with satisfactory potency and selectivity, either with a competitive or with a non-competitive mechanism of action. In particular, a number of cyclopropane-1,2-dicarboxylic acid derivatives were synthetized, leading to the identification of cis-(±)-cyclopropane-1,2-dicarboxylic acid, that interacts with the enzyme in a non-covalent manner and shows an affinity of ̴ 240 µM. However, as described herein, the modification of the hit compound was found to be particularly problematic.
The search for covalent inhibitors, led to the synthesis of a second class of compounds that interact with the PLP moiety of the enzyme, and inhibit the enzyme in a time–dependent manner.
This finding opens the possibility of exploring a new class of SR covalent inhibitors.Thu, 27 Mar 2014 23:00:00 GMThttp://hdl.handle.net/1889/25112014-03-27T23:00:00ZNew perspectives of vinylogy. Eco-friendly and organocatalytic methods for the selective synthesis of highly diversified molecular scaffoldshttp://hdl.handle.net/1889/2510
Titolo: New perspectives of vinylogy. Eco-friendly and organocatalytic methods for the selective synthesis of highly diversified molecular scaffolds
Autori: Dell'Amico, Luca
Abstract: Since its first conceptualization by R. C. Fuson in 1935, the vinylogy principle has been increasingly attracted the curiosity of organic chemists while challenging their abilities. The design and development of new synthetic methodologies based on the application of this principle experienced an exponential growth in the last few years, especially when this topic was connected to other emerging fields such as stereocontrolled synthetic methods and enantioselective catalysis. Thus, about 80 years later, I am presenting a summary of the work I did during my PhD studies, which covered the period 2010-2013, whose central theme is based on the application of the vinylogy principle toward new synthetic methods. Different strategies were explored, in order to promote novel vinylogous transformations. In the first part of the work, the use of water, as an eco-friendly reaction medium as well as reaction promoter, was successfully investigated, with the development of the first vinylogous Mukaiyama Michael and Mannich reactions. The synthetic potential of the disclosed methods were highlighted by the total synthesis of highly functionalized pyrroles and a stereoisomer of oseltamivir. Further evolution of these concepts culminated with the development of unprecedented organocatalyzed reactivity patterns, involving the use of newly designed vinylogous azlacatones or butyrolactones in enantioselective Michael addition reactions to alfa, beta-unsaturated (or alfa, beta, gamma, delta-unsaturated) aldehydes, including a very first example of doubly vinylogous transformation (vinylogous 1,6-addition). Phenylogous reactions were also investigated through enantioselective organocatalytic methods. Finally, in the last part of this thesis, a still on-going project is presented, focusing on the development of unprecedented regio-divergent vinylogous carbon-carbon bond-forming reactions towards multifunctional carbocycles.
Part of the work herein presented was developed during my fruitful visiting period at the Aarhus University (DK), under the supervision of Prof. K. A. Jørgensen (Chapters VI and VII). The remaining part of the work was developed at the Parma University (I), (Chapters II, III, IV and VIII) under the supervision of Prof. F. Zanardi.
During my research activity, I have been working with many talented and enthusiastic chemists. I want to highlight that, without their help, their teachings, the discussions, the laughter and deep friendship, the development of my work would have been impossible.Tue, 31 Dec 2013 23:00:00 GMThttp://hdl.handle.net/1889/25102013-12-31T23:00:00ZModelling studies of bitter taste, glucocorticoid and VEGFR2 receptors and their ligandshttp://hdl.handle.net/1889/2509
Titolo: Modelling studies of bitter taste, glucocorticoid and VEGFR2 receptors and their ligands
Autori: Capelli, Anna Maria
Abstract: Modelling studies of bitter taste receptors and their ligands
The human bitter taste receptor gene family (TAS2R) belongs to the Frizzled/Taste2 subfamily of the G-protein coupled receptors (GPCR) superfamily. TAS2R are expressed on the tongue in bitter taste receptor cells co-expressing specific signal transduction components like Ggustducin and are able to detect stimuli of only one taste quality. Recently these receptors have been identified in isolated human airway smooth muscle cells (ASM). Besides, in the literature it has been reported that bitter taste receptor agonists such as saccharin, chloroquine and denatonium can evoke increased intracellular calcium in ASM eliciting relaxation of isolated ASM and dilation of airways greater than that showed by -adrenergic receptor agonists. Furthermore, inhaled bitter taste compounds can decrease airway obstruction in a mouse model of asthma. In light of these evidences this novel pathway looks attractive and might be exploited to identify novel compounds to treat asthma and chronic obstructive pulmonary disease (COPD). During the 1st year of my PhD course, chemoinformatics analyses of known bitter tastants aimed at finding common structural features and pharmacophores were performed. Besides, the generation of hTAS2R10, hTAS2R14 and hTAS2R31 receptor models was carried out together with docking studies of a few known bitter agonists in the putative binding sites of these receptor subtypes. Results of these experiments were validated in light of site-directed mutagenesis experiments available in the literature and provided useful suggestion about additional site-directed mutagenesis studies and chimera constructs to further validate these models. Results of these studies were presented as a poster at the Research Gordon Conference on “Computer Aided Drug Design”, held at Mount Snow Resort, West Dover, VT, in 2011.
Elucidation of glucocorticosteroids unbinding pathways from the glucocorticoid receptor
Glucocorticoids are endogenous steroid hormones that regulate essential biological functions including metabolism, growth, and apoptosis. Glucocorticoids and structurally related drugs represent the most effective anti-inflammatory agents to treat several inflammatory conditions. However, the clinical use of such drugs is hampered by severe side effects. Therefore, the development of novel glucocorticoid receptor (GRs) modulators with increased therapeutic index is impelling. Herein, using steered molecular dynamics (SMD) simulations a detailed picture of the unbinding process of three clinically relevant GR modulators from GR ligand binding domain is provided. The SMD protocol described can be used to prioritize the synthesis of structural analogues on the basis of their potential of mean forces (PMFs) and calculated unbinding energies. Moreover, these results are instrumental to explain at atomic resolution the reduced ability of dexamethasone to activate the naturally occurring mutant I747M-GR, which is implicated in rare familial glucocorticoid resistance, clinically characterized by glucocorticoids insensitivity. Results of these simulations were presented as a poster at the ACS Meeting held in Philadelphia in 2012 and published in the Journal of Medicinal Chemistry in September 2013.
Modelling studies of VEGFR2 and its inhibitors
Vascular Endothelial Growth Factor Receptor 2 (VEGFR2) is a type III receptor tyrosine kinase (RTK) in the PDGFR family. VEGF preferably binds this receptor and triggers important signaling pathway implicated in the process of vasculogenesis and angiogenesis. VEGFR2 is a clinically validated target to treat Renal Cell Carcinoma (RCC). Recently the crystal structures of sunitinib and sorafenib, two clinically relevant TKIs, bound to the kinase domain of VEGFR2 have been solved together with the enzyme juxtamembrane (JM) domain, highlighting the critical role played by this enzyme portion to form the inactivated state of VEGFR2 kinase which binds these ligands. The construct utilized to generate these VEGFR2 crystal structures was also used to measure the potencies, time dependencies and selectivity of a wide panel of TKI, including sunitinib and sorafenib. Besides, kinetic parameters (koff) were detected for both these inhibitors and the new construct. While sunitinib is a prototypical type IV inhibitor, showing short dissociative half-life from VEGFR2, sorafenib is an exemplar of type II inhibitor, characterized by long dissociative half-life from VEGFR2 receptor. Herein, a preliminary detailed atomistic description of the unbinding process of sorafenib and sunitinib from VEGFR2 was unveiled by using SMD simulations. While sunitinib exits the ATP binding site from the cavity entrance, sorafenib moves towards the JM domain, causing a change in the orientation of the C-helix. While no rupture point could be identified in the force profile of sunitinib, analysis of the average force profile of sorafenib reveals that the rupture point involves the water-assisted breakage of sorafenib interaction with the hinge amino acid C919 and subsequently the disruption of the hydrogen bond of the ligand carbonyl urea moiety with D1046 (DFG-out motif). At the same time the hydrogen bond interactions established between the NH ligand urea moiety and E885 in the C-helix likely delay ligand exit. Besides, the phenyl ring decorated with chlorine and trifluoromethyl groups makes hydrophobic interactions with some hydrophobic residues in C-helix, which would further facilitate the ligand unbinding process. More robust conclusions will be drawn once the simulations of more ligand frames have been performed.Thu, 27 Mar 2014 23:00:00 GMThttp://hdl.handle.net/1889/25092014-03-27T23:00:00ZThe challenging world of in silico drug design: tools development and applicationshttp://hdl.handle.net/1889/2508
Titolo: The challenging world of in silico drug design: tools development and applications
Autori: Beato, Claudia
Abstract: In the attempt to reduce time and costs of the drug discovery process, computational strategies have been looked as the possible solution. Despite still far from being the answer of all the problems, the use of computational approaches is now well established in the drug discovery pipeline. In the course of the years a lot of techniques have been developed and now are applied to several phases of drug discovery and development. In the present thesis is summarized the work conducted in three different projects carried out during my PhD, that allowed me to exploit different computational strategies.
The goal of the main project was the optimization and the validation of the performance of a new drug discovery software, LiGen, result of the collaboration between the Italian pharmaceutical company Dompé, the Italian supercomputing center CINECA and our research group. LiGen was developed to perform protein surface analysis, molecular docking and de novo design; during this project we focused our attention mainly on the first two tools, LiGenPocket, aimed at the binding site analysis and structure-based pharmacophore definition, and LiGenDock, the molecular docking engine. Even if seldom used in computational chemistry, we decided to apply the Design of Experiments (DoE) methodology to optimize parameters controlling LiGenPocket and LiGenDock. At first we applied a fractional factorial design to screen the set of user-adjustable parameters to identify those having the largest influence on the accuracy of the results and then we optimize their values, to ensure the best performance in pose prediction and in virtual screening. Afterwards the results have been also compared with those obtained by two popular docking programs, namely Glide and AutoDock, for pose prediction, Glide and DOCK6 for Virtual Screening.
The second project was the investigation of the binding mode of a series of compounds based on the 2-aminonicotinic 1-oxide scaffold and developed by our synthetic laboratory, to inhibit the 3-hydroxyanthranilic acid dioxygenase (3-HAO), an enzyme of the kynurenine pathway. 3-HAO is responsible for the production of the neurotoxic tryptophan metabolite quinolinic acid (QUIN); elevated brain levels of QUIN has been connected to several neurodegenerative diseases therefore 3-HAO inhibition may be a useful strategy for Huntington’s diseases and Alzheimer’s diseases among the others. To predict the most probable binding mode, compounds and the binding site have been characterized at quantum mechanical level, due to the presence of a catalytic iron atom in the binding site. Molecular docking was then used to predict the binding mode of the compounds and to investigate the effects of the substituents at the pyridine ring.
The third project was related to the creation of a database of functional groups to screen chemical libraries, in order to reject or to flag these functionalities in libraries used for virtual screening purposes, in relation to their potential toxicity. The functional groups have been collected from different sources and have been classified according to the type of risk they may be related. This collection of compounds has been enriched also with compounds that have been identified as “frequent hitters”, indicating compounds often interfering in vitro assays, especially in HTS. The final database is therefore divided in three group, one collecting the intrinsically reactive moieties, one with functional groups susceptible to biotransformation into reactive metabolites and one containing substructures frequently identified as false positives in experimental tests.Fri, 28 Feb 2014 23:00:00 GMThttp://hdl.handle.net/1889/25082014-02-28T23:00:00ZInterfering with the excitatory amino acids signalling in the brain for the design of novel neuroprotective agentshttp://hdl.handle.net/1889/2249
Titolo: Interfering with the excitatory amino acids signalling in the brain for the design of novel neuroprotective agents
Autori: Vallerini, Gian Paolo
Abstract: A complex network of central synaptic transmission is regulated, in vertebrates, by simple amino acids: GABA, with inhibitory effects, and glutamate, the most abundant excitatory amino acid in the CNS. These two fundamental neurotransmitters are responsible for the homeostasis of all the CNS functions, from post-natal developmental age to the entire adult life. Even slight dysregulations of GABA-ergic and glutamat-ergic systems underlie the genesis and the progression of a number of neurological pathologies, both neurodegenerative and psychiatric disorders. GABA-based drugs are widely used in clinic for the treatment of different pathological states, such as anxiety, epilepsy and neuropathic pain. Conversely, the dissociative anaesthetic ketamine and the pro-cognitive agent memantine, are the only glutamatergic drugs which have found clinical use, despite the large volume of evidences that unequivocally link glutamate to CNS diseases.
Due to the tight linkage between glutamate transmission and several metabolic cascades, both in periphery and in the CNS, the modulation of enzymatic pathways, leading to the biosynthesis of metabolites able to interfere with the glutamatergic system, offers a viable way to design novel therapeutic approaches for the treatment of a wide spectrum of invalidant neurological conditions. The kynurenic pathway of tryptophan metabolism is the main route of degradation of the essential, proteinogenic amino acid L-tryptophan in mammals and is responsible for the production of several neuroactive compounds, most of which endowed with specific actions towards glutamate receptors: i) kynurenic acid, wide spectrum competitive antagonist of ionotropic glutamate receptors and negative allosteric modulator of α7 nicotinic acetylcholine receptors, with neuroprotective properties, ii) 3-hydroxykynurenine, neurotoxic for its ability to generate free radical species, iii) xanthurenic acid, modulator of Group II metabotropic Glu receptors, iv) cinnabarinic acid, selective mGlu4 orthosteric partial agonist and v) quinolinic acid (QUIN), an endogenous excitotoxin acting as a selective NMDARs agonist. Since the inhibition of the production of QUIN has been proposed as a valid approach for the drug discovery in the field of neurological disorders, this doctoral thesis is aimed at the design and synthesis of novel inhibitors of the enzyme responsible for the biosynthesis of QUIN, namely 3-hydroxyanthranilate 3,4-dioxygenase (3-HAO).
Previously described 3-HAO inhibitors are halogenated substrate analogues and are characterized by high chemical instability, due to the common o-aminophenol core. In this work, a series of novel potential 3-HAO inhibitors has been designed and synthesized, based on the chemically stable pyridine N-oxide nucleus. Biological tests have shown interesting activity for three of the synthesized compounds in vitro, with IC50 values ranging between 0.6 μM and 100 μM. A preliminary SAR profile has been drawn for this class of 3-HAO inhibitors, based on the relative activities of test compounds and on docking studies performed by our group of molecular modelling. The most active compound, 2-amino-6-methylnicotinic acid 1-oxide, was also tested in vivo and resulted active, showing modulatory activity on the production of different kyurenine pathway metabolites, in lesioned rat brain.
These findings demonstrated the suitability of the 2-aminopyridine-1-oxide scaffold for the design of novel, chemically stable 3-HAO inhibitors which, being active in vivo, open the road to further studies, aimed at the full characterization of the involvement of the kynurenine pathway in the onset and the progression of neurodegenerative and autoimmune diseases, such as Huntington’s disease and multiple sclerosis.Wed, 27 Mar 2013 23:00:00 GMThttp://hdl.handle.net/1889/22492013-03-27T23:00:00ZNitrogen-embedding heterocyclic nucleophiles in catalytic asymmetric vinylogous Mannich reactionshttp://hdl.handle.net/1889/2245
Titolo: Nitrogen-embedding heterocyclic nucleophiles in catalytic asymmetric vinylogous Mannich reactions
Autori: Ranieri, Beatrice
Abstract: the main objectives of this PhD program were focused on the development of the Mannich reaction in the vinylogous field. Intersecting the growing principles of asymmetric and organocatalysis, different protocols were developed: two for catalytic asymmetric vinylogous Mukaiyama-Mannich reaction with nitrogen-based silicon dienolates; they were successfully applied to aromatic and aliphatic aldimine donors. The ongoing project with 3-alkenyl-2-oxindoles as d4 donor progeny is also described: the final aim is the synthesis of 2,4-perhydro-alpha-carboline, natural and medicinal occurring scaffolds. A chapter is dedicated to the project in prof. Romo research gruop at texas A&M university: the development of a short, scalable and economical synthesis towards homobenzotetramisole and related organocatalysts.Thu, 28 Feb 2013 23:00:00 GMThttp://hdl.handle.net/1889/22452013-02-28T23:00:00ZSmall-molecule modulators of receptor tyrosine kinases as potential antitumor agentshttp://hdl.handle.net/1889/2243
Titolo: Small-molecule modulators of receptor tyrosine kinases as potential antitumor agents
Autori: Russo, Simonetta
Abstract: Receptor tyrosine kinases (RTKs) play key roles in signal transduction pathways, thereby affecting many important cellular processes. Dysregulation of RTK activity can cause significant alterations in normal physiological functions, contributing to tumor formation. Therefore, RTKs have become prime targets in cancer therapy. Two main strategies could be adopted to block aberrant RTK activity: i) the use of agents directly interacting with the intracellular kinase domain or ii) the use of agents able to impede the ligand-receptor interaction, by occupying the extracellular ligand-binding site of the receptor. In the present thesis, design and synthesis of two classes of compounds that reflect the two aforementioned strategies of RTK blockage are presented.
The first class of compounds consists of irreversible inhibitors directed against the ATP-binding site of EGFR, a validated anticancer drug target. This series of novel EGFR inhibitors was designed with the aim to reduce the high reactivity and, consequently, the off-target toxicity of the traditional irreversible inhibitors, preserving their ability to covalently alkylate a cysteine residue (cys797) of the target. These compounds were obtained combining a 3-aminopropanamide “warhead” with a 4-anilinoquinazoline or a 4-anilinoquinoline-3-carbonitrile driving portion.
The second class of compounds consists of small molecules targeting the Eph-ephrin system, which has been found to be involved in oncogenic and angiogenic phenomena. These compounds were prepared starting from lithocholic acid (LCA), recently identified as a competitive and reversible antagonist at the EphA2 receptor. These LCA derivatives interfere with the Eph-ephrin interaction, by recognizing the ephrin-binding domain situated on the extracellular portion of the Eph receptor. In particular, a series of α-amino acid conjugates of LCA was synthesized, achieving potent compounds that could be used as pharmacological tools to further investigate the role of the Eph-ephrin system in cancer.Thu, 28 Feb 2013 23:00:00 GMThttp://hdl.handle.net/1889/22432013-02-28T23:00:00ZSviluppo di strategie formulative atte a migliorare la stabilità e la veicolazione di preparati inalatorihttp://hdl.handle.net/1889/2241
Titolo: Sviluppo di strategie formulative atte a migliorare la stabilità e la veicolazione di preparati inalatori
Autori: Miozzi, Michele
Abstract: Lo scopo di questo lavoro di tesi è stato lo studio di sospensioni pressurizzate per inalazione a base di formoterolo fumarato. La ricerca è stata rivolta alla produzione e alla caratterizzazione di polveri di formoterolo fumarato con caratteristiche superficiali modificate rispetto alla materi prima. Le particelle di formoterolo sono state rivestite con diversi acidi grassi e in diverse proporzioni mediante la tecnica spray drying, partendo da sospensioni di farmaco in una soluzione contenente l’acido grasso. L’essiccamento a spruzzo di una sospensione del farmaco ha permesso di mantenere inalterata la struttura cristallina della materia prima di partenza, il contenuto di attivo e le dimensioni delle particelle. Le microparticelle rivestite con acidi grassi hanno dato origine a sospensioni più stabili nel propellente HFA134, rispetto al formoterolo fumarato materia prima. L’utilizzo di canister rivestiti e di polveri rivestite spray dried nelle formulazioni pMDI miglioravano i valori di dose emessa e i parametri di respirabilità e garantivano una maggiore stabilità nel tempo, rispetto alle formulazioni a base di formoterolo fumarato non trattato.; The aim of this work was to develop formoterol fumarate suspensions in a pMDI (pressurized metered dose inhaler) system. Formoterol particles with modified surface characteristics were manufactured by spray drying technology. A suspension of the drug was spray dried with different amounts of fatty acids. This process did not affect the crystallinity, the drug content, and the particle size of the raw material. Spray dried powders led to more stable pMDI suspensions compared to unprocessed formoterol. The combination between coated powders, obtained by spray drying, and the use of coated canisters in pMDI products improved the emitted dose values and the respirability parameters, compared to the products containing formoterol raw material.Wed, 17 Apr 2013 22:00:00 GMThttp://hdl.handle.net/1889/22412013-04-17T22:00:00Z